This invention relates to a barge-carrying waterborne vessel.
In our U.S. Pat. No. 3,913,512, issued Oct. 21, 1975, we described such a vessel of primary use in relatively shallow or coastal waters. In circumstances where a substantial width of ocean is to be crossed, as for example passage from New Orleans to the U.S.S.R., or from the Persian Gulf to San Francisco, or New York, some problems arise which require careful consideration. In high winds and storms at sea, considerable problems may arise from water inside the hold. Such water may tend to get into and fill barges or other containers, for in many instances these are not tightly enough sealed at their upper ends to prevent the entrance of such water, and in others their closures may be too weak to withstand it for long under difficult conditions. Therefore, while the vessel itself would be able to withstand the storms while carrying the barges and other containers, the barges themselves can be damaged or filled with water if not correctly adapted to such conditions, resulting in eventual damage to the cargo. Such problems might be solved by using barges having stronger and tighter closures, but the barges presently available cannot do so.
The present invention is directed to a solution of these problems.
In addition to the problems already mentioned, other problems arise when the vessel is to be used to carry a substantial load on deck in addition to the barges or other carriers inside the hold. In these instances the transportation of the barges may comprise a smaller fraction of the load than the cargo carried on deck or at least may not greatly exceed it. In such instances as these, it would be better to run the vessel dry, in order to accommodate the substantial dead weight cargo, for it is clear that a hull which is substantially open to the ocean can carry less dead weight than a vessel with a dry hold. At the same time, it is a great convenience to be able to load and unload by flotation of the cargo. However, there is an apparent difficulty in providing flotation loading and unloading and also enabling a vessel to carry a large dead weight; the vessel in our earlier patent is not able to do this on long ocean voyages.
The present invention also solves these problems by both providing flotation loading and unloading and also the ability to carry a substantial cargo dead weight.